A wafer for a semiconductor device, an electronic part, or the like is subjected to various steps such as cutting or polishing in the course of manufacture. In recent years, according to development of a semiconductor technique, miniaturization and multilayer wiring of design rule of a semiconductor integrated circuit advance, and a diameter enlargement of a wafer also progress for achieving cost reduction. Therefore, when a layer formed with a pattern is formed thereon with a pattern of the next layer like the conventional art as it is, it becomes difficult to form an excellent pattern on the next layer due to undulation of the precedent layer and a defect or the like may occur easily.
Therefore, a planarizing process for planarizing a surface of a layer formed with a pattern and subsequently forming a pattern of the next layer is implemented. CMP is frequently used in the planarizing process. Polishing of a wafer utilizing CMP is performed by holding the wafer by a polishing head, pressing the wafer to a rotating polishing pad, with a predetermined pressure, and supplying slurry that is mixture of abrading agent and chemicals between the polishing pad and the wafer.
In the polishing utilizing CMP, the slurry supplied on the polishing pad is an important factor influencing a polished shape of a wafer. In order to polish a wafer evenly, it is necessary to supply the slurry to the polishing pad evenly.
When the slurry is supplied to the polishing pad surface excessively, the polishing cost increases in mass production, so that it is also necessary to supply slurry onto the polishing pad in small amounts efficiently and evenly.
A groove is generally formed on a surface of a polishing pad. The groove is generally for distributing slurry to the whole surface of the polishing pad, and, for example, it is conventionally known that a plurality of grooves are formed radially and depths of the respective grooves at an outer peripheral portion of the polishing pad are made shallow in order to perform distribution of slurry to the polishing pad surface efficiently (for example, see Patent Document 1).
However, slurry only when it is conveyed to a surface portion of the polishing pad contributes to polishing to a wafer instead of supplying of the slurry into the grooves. Therefore, how to supply slurry to the surface portion of whole polishing pad efficiently is important.
On the other hand, for example, a slurry supplying apparatus that introduces slurry onto a polishing pad through a slurry transport pipe, a wafer polishing apparatus that can change a slurry supplying position using a movable arm, or a polishing apparatus provided with a squeegee that sprays slurry in a mist and spreads the slurry on a polishing face, or the like is known (for example, see Patent Document 2, 3, or 4).
[Patent Document 1] JP-A-2005-177934 (Page 4 and FIG. 1)
[Patent Document 2] JP-A-2004-63888 (Page 4 and FIG. 3)
[Patent Document 3] JP-A-11-70464 (Page 4 and FIG. 2)
[Patent Document 4] JP-A-10-296618 (Page 4 and FIG. 9)